Add linting to grunt test job

* Add grunt-jscs and .jscsrc (lint trailing whitespaces and indentation length)
* Cleanup .jshintrc (use globals instead of deprecated predefs)
* Add Gruntfile.js and *.json linting to npm test

N.B. This does not lint the whole src/ directory during grunt test but
this should definitely be our goal. Please try to de-lint any js files
you touch during development using a texteditor that support linting
(Sublime Text 3 and SublimeLinter 3 with jshint/jscs plugins work great)

.jscsrc

@@ -0,0 +1,4 @@
+{
+  "disallowTrailingWhitespace": true,
+  "validateIndentation": 2
+}

.jshintrc

@@ -1,39 +1,34 @@
 {
-	"indent": 2,
-	"strict": true,
-	"globalstrict": true,
-	"node": true,
-	"browser": true,
-	"nonew": true,
-	"curly": true,
-	"eqeqeq": true,
-	"immed": true,
-	"newcap": true,
-	"regexp": true,
-	"evil": true,
-	"eqnull": true,
-	"expr": true,
-	"trailing": true,
-	"undef": true,
-	"unused": true,
+  "strict": true,
+  "globalstrict": true,
+  "node": true,
+  "browser": true,
+  "nonew": true,
+  "curly": true,
+  "eqeqeq": true,
+  "immed": true,
+  "newcap": true,
+  "regexp": true,
+  "evil": true,
+  "eqnull": true,
+  "expr": true,
+  "undef": true,
+  "unused": true,
 
-	"predef": [
-			"console",
-			"Promise",
-			"importScripts",
-			"process",
-			"Event",
-			"self",
-			"describe",
-			"it",
-			"sinon",
-			"mocha",
-            "before",
-            "beforeEach",
-            "after",
-            "afterEach"
-	],
-
-	"globals": {
-	}
+  "globals": {
+    "console": true,
+    "Promise": true,
+    "importScripts": true,
+    "process": true,
+    "Event": true,
+    "self": true,
+    "describe": true,
+    "it": true,
+    "sinon": true,
+    "mocha": true,
+    "before": true,
+    "beforeEach": true,
+    "after": true,
+    "afterEach": true
+  }
 }

Gruntfile.js

@@ -1,10 +1,13 @@
+'use strict';
+
 module.exports = function(grunt) {
 
   var version = grunt.option('release');
   var fs = require('fs');
+  var browser_capabilities;
 
-  if (process.env.SELENIUM_BROWSER_CAPABILITIES != undefined) {
-    var browser_capabilities = JSON.parse(process.env.SELENIUM_BROWSER_CAPABILITIES);
+  if (process.env.SELENIUM_BROWSER_CAPABILITIES !== undefined) {
+    browser_capabilities = JSON.parse(process.env.SELENIUM_BROWSER_CAPABILITIES);
   }
 
   // Project configuration.
@@ -102,7 +105,20 @@ module.exports = function(grunt) {
       }
     },
     jshint: {
-      all: ['src/**/*.js']
+      src: ['src/**/*.js'],
+      build: ['Gruntfile.js', '*.json'],
+      options: {
+        jshintrc: '.jshintrc'
+      }
+    },
+    jscs: {
+      src: ['src/**/*.js'],
+      build: ['Gruntfile.js'],
+      options: {
+        config: ".jscsrc",
+        esnext: false, // If you use ES6 http://jscs.info/overview.html#esnext
+        verbose: true, // If you need output with rule names http://jscs.info/overview.html#verbose
+      }
     },
     jsdoc: {
       dist: {
@@ -189,6 +205,7 @@ module.exports = function(grunt) {
   grunt.loadNpmTasks('grunt-text-replace');
   grunt.loadNpmTasks('grunt-jsbeautifier');
   grunt.loadNpmTasks('grunt-contrib-jshint');
+  grunt.loadNpmTasks('grunt-jscs');
   grunt.loadNpmTasks('grunt-jsdoc');
   grunt.loadNpmTasks('grunt-mocha-istanbul');
   grunt.loadNpmTasks('grunt-mocha-test');
@@ -242,12 +259,12 @@ module.exports = function(grunt) {
       if (err) {
         return done(err);
       }
-    done();
+      done();
     });
   });
 
   // Test/Dev tasks
-  grunt.registerTask('test', ['copy:zlib', 'mochaTest']);
+  grunt.registerTask('test', ['jshint:build', 'jscs:build', 'copy:zlib', 'mochaTest']);
   grunt.registerTask('coverage', ['copy:zlib', 'mocha_istanbul:coverage']);
   grunt.registerTask('coveralls', ['copy:zlib', 'mocha_istanbul:coveralls']);
   grunt.registerTask('saucelabs', ['default', 'copy:browsertest', 'connect', 'saucelabs-mocha']);

package.json

@@ -42,6 +42,7 @@
     "grunt-contrib-jshint": "~0.12.0",
     "grunt-contrib-uglify": "~0.11.0",
     "grunt-jsbeautifier": "~0.2.10",
+    "grunt-jscs": "^2.7.0",
     "grunt-jsdoc": "~1.1.0",
     "grunt-mocha-istanbul": "^3.0.1",
     "grunt-mocha-test": "~0.12.7",